refactor: combine process column code

[ClementTsang]

Description

A description of the change, what it does, and why it was made. If relevant (such as any change that modifies the UI), please provide screenshots of the changes:

This combines some of the kinda duplicated code around process columns across options and the actual data.

Issue

If applicable, what issue does this address?

Closes: #

Testing

If relevant, please state how this was tested. All changes must be tested to work:

If this is a code change, please also indicate which platforms were tested:

• Windows
• macOS
• Linux

Checklist

If relevant, ensure the following have been met:

• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, doc pages, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts
• If relevant, new tests were added (don't worry too much about coverage)

[codecov]

Codecov Report

Attention: Patch coverage is 64.60177% with 40 lines in your changes missing coverage. Please review.

Project coverage is 41.84%. Comparing base (103c4f6) to head (835ec66).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/widgets/process_table/process_columns.rs	61.19%	26 Missing ⚠️
src/widgets/process_table.rs	78.04%	9 Missing ⚠️
src/widgets/process_table/process_data.rs	0.00%	3 Missing ⚠️
src/main.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1622      +/-   ##
==========================================
- Coverage   41.89%   41.84%   -0.05%     
==========================================
  Files         114      114              
  Lines       17639    17621      -18     
==========================================
- Hits         7389     7374      -15     
+ Misses      10250    10247       -3     

Flag	Coverage Δ
macos-12	37.26% <64.60%> (-0.06%)	⬇️
ubuntu-latest	43.62% <64.60%> (-0.05%)	⬇️
windows-2019	37.17% <64.60%> (-0.06%)	⬇️

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